The present disclosure relates to guidance and tracking systems for tracking handheld implements, such as medical instruments. More particularly, the present disclosure relates to active and passive marker arrangements for surgical guidance and tracking of medical instruments.
Surgical guidance enables surgeons to localize the position of surgical instruments relative to the human body without having full visual access during surgery. Surgical guidance is routinely used in surgeries of the spine, brain, hip or other organs.
In general, surgical guidance consists of two steps: The first step includes the acquisition of a three dimensional (3D) representation of relevant portion of the body. This step may involve a single or multiple imaging modalities such as computer tomography (CT), magnetic resonance tomography (MRT), positron emission tomography (PET) and ultrasound (US). The 3D representation may be acquired before and/or during the surgical procedure. In the second step, the spatial position of the body and the spatial relation of the surgical instruments to the position of the body are tracked during the surgery. The spatial position of the body is correlated to its 3D representation using specific image registration techniques. After registration, the spatial position of the surgical instruments can be displayed with a 3D representation of the body for the surgeon.
Typically, optical-based systems are used for the tracking of the spatial positions during the surgery. These systems are based on two cameras that detect the positions of at least three markers attached to the tracked surgical instruments (for example, mounted with LEDs as disclosed in U.S. Pat. No. 5,921,992, or mounted with reflective probes as disclosed in U.S. Pat. No. 6,061,644).
There are many possible designs for the attachment of these markers to surgical instruments that include a longitudinal shaft (for example, U.S. Pat. Nos. 6,021,343, 7,226,456 B2, 6,556,857 B1, 7,166,114 B2, and US Patent No. 2002/0077540 A1). However, most of these designs include a common characteristic that the cameras of the optical tracking system are oriented to view the side of the shaft of the surgical instruments. The markers are therefore aligned along the instrument shaft.
In other applications, the tracking system may be oriented directly above the surgical incision, such that the tracking system “looks” into the incision. These applications include arrangements for which the tracking system is integrated into the surgical lighting system (for example, U.S. Pat. No. 7,224,472), or arrangements for which the tracking system is integrated into a system for performing optical topology imaging of anatomy within the incision (for example, U.S. Pat. Nos. 5,531,520 and 5,999,840 and PCT Patent Application PCT/CA2011/050257).